The present invention is a system for safely and automatically delivering viscous chemicals to a number of destinations, such as a number of industrial clothes washers. An important feature of the invention is that a single set of chemical pumps with a single manifold and a single distribution tube are used to deliver chemicals to multiple destinations. In addition, the system has "proof of flow" logic for verifying that specified chemicals are dispensed into the manifold, and "proof of delivery" logic for verifying that each chemical arrives at its specified destination. Another aspect of the invention is that every chemical delivery event is followed by a water flush cycle so as to reduce corrosion and chemical induced equipment failures.
Chemicals are automatically metered and diluted as they are delivered to a specified destination. The system automatically dilutes viscous chemicals so that viscous chemicals can be delivered using low pressure fluid lines.
The ability to dilute and deliver viscous chemicals with low pressure allows the delivery of chemicals to relatively remote locations with low cost equipment.
The system's chemical pumps are automatically recalibrated on a periodic basis. This provides accurate metering of chemicals, and also allows the specification of chemical quantities in standard units such as ounces or milliliters.
The present invention deals with a number of problems that have long plagued commercial laundries and other cleaning systems which use caustic chemicals. For instance, it is less expensive to transport viscous, undiluted chemicals to the users of chemicals, but it has generally been difficult to accurately meter the amount of such chemicals used and therefore many commercial chemical delivery systems either avoid the use of viscous chemicals or suffer from the effects of using inconsistent quantities of chemicals. The chemical metering system of the present invention eliminates this problem by providing accurate metering of liquid chemicals.
A problem in many chemical delivery systems is corrosion of the pumps and tubes used to transport chemicals. Caustic chemicals attack many materials and require the frequent replacement of equipment. The present invention virtually eliminates this problem by automatically flushing all critical components with water after every chemical delivery. After each chemical is pumped, the pump is reversed, so that the pump (or the pump's tube) is not exposed to chemical for most of its life.
When using peristaltic pumps, another source of tube failure in many chemical delivery systems is back pressure on the output of the chemical pump. The accuracy of metering of chemicals is also affected by output pressure.
The present invention eliminates this problem by providing a relative vacuum on the output of the chemical pumps.
Caustic and viscous chemicals are often not metered, but rather pumped for a specified amount of time, because flow meters are expensive and the chemicals corrode and destroy the flow meters. The present invention automatically and accurately recalibrates each chemical metering pump. In addition, the present invention uses a single flow meter to measure all chemicals, thereby substantially reducing the cost of metering chemicals. Furthermore, this single flow meter is placed upstream of the system's manifold to avoid contact with and corrosion by the chemicals being dispensed.
Another problem in many chemical delivery systems is the need to prime the pumps which draw chemicals from a chemical supply. This is a problem because it is a task that the system operator must remember to perform. Failure to prime the chemical pumps results in the delivery of an improper amount of chemical during initial operation of the pumps, until the pumps have been primed through repeated use. The present invention solves this problem by automatically priming each chemical pump every time the pump is used. This is done by running the pump until the presence of the chemical is detected by a conductivity cell.
Prior art systems typically use a distinct delivery tube for each different chemical so as to avoid reactions between the various chemicals used. The present invention uses a single chemical distribution tube. Inadvertent chemical reactions are prevented by separating successively delivered chemicals with a sufficient amount of water so as to insure that the two chemicals do not react.
Another feature of the present invention is that it eliminates the problem of chemicals dripping from the ends of chemical delivery tubes. Such drips can damage equipment as well as clothing and people, and can cause unexpected chemical reactions between successively used chemicals. The present invention eliminates this problem by following every chemical delivery with a water flush.